Electronically steerable array antenna for satellite TV

Abstract

An antenna is arranged to be mounted on a vehicle and to receive signals, such as television signals, from a geosynchronous satellite. In a preferred arrangement the antenna includes two or three linear arrays of antenna element rows. The arrays each have a linear direction perpendicular to broadside or pointing direction and are angularly oriented with respect to each other to distribute the linear directions around the directions of a plane perpendicular to the broadside direction. The element rows are arranged to form at least one row antenna beam in a direction which is offset from the broadside pointing direction in a plane perpendicular to the linear direction. Phase shifters are arranged to change the phase of signals transmitted or received by antenna elements of each of the rows and a signal combiner/divider is arranged to couple signals between the phase shifters and a transmitter or receiver port of the antenna.

1 . An antenna having a pointing direction, comprising a linear array of antenna element rows, said array having a linear direction perpendicular to said pointing direction, each of said element rows being arranged to form at least one row antenna beam in a direction which is offset from said pointing direction in a plane perpendicular to said linear direction, phase shifters arranged to change the phase of signals transmitted or received by antenna elements of each of said rows and a signal combiner/divider arranged to couple signals between said phase shifters and a transmitter or receiver port of said antenna.  
   
   
       2 . An antenna as specified in  claim 1  wherein said row antenna beams of said element rows are offset from said pointing direction by an angle of 30 to 60 degrees.  
   
   
       3 . An antenna as specified in  claim 1  wherein said antenna element rows are arranged to provide two simultaneous row antenna beams, said two row antenna beams being offset from said pointing direction by opposite and substantially equal angles.  
   
   
       4 . An antenna as specified in  claim 3  wherein said antenna element rows comprise a plurality of antenna elements having a selected spacing and a signal combiner/divider arranged to provide signals to or from said elements of each row with opposite phase for adjacent elements.  
   
   
       5 . An antenna as specified in  claim 1  wherein said antenna element rows are arranged to provide one of two selectable row antenna beams, said selectable row antenna beams being offset from said pointing direction by opposite and substantially equal angles.  
   
   
       6 . An antenna as specified in  claim 5  wherein said antenna element rows comprise a plurality of antenna elements having selected spacing, a coupling matrix connected to said elements having at least two ports, each port corresponding to one of said selectable beams and a switch for selecting one of said ports.  
   
   
       7 . An antenna having a pointing direction, comprising two linear arrays of antenna element rows, each said array having a linear direction perpendicular to said pointing direction and perpendicular to the linear direction of the other array, each of said element rows being arranged to form at least one row antenna beam in a direction which is offset from said pointing direction in a plane perpendicular to said linear direction of its corresponding array, phase shifters arranged to change the phase of signals transmitted or received by antenna elements of each of said rows and a signal combiner/divider for each array arranged to couple signals between said phase shifters and a transmitter or receiver port of said array, and a switch for selecting one of said arrays for connection to a transmitter or receiver.  
   
   
       8 . An antenna as specified in  claim 7  wherein said row antenna beams of said element rows are offset from said pointing direction by an angle of 30 to 60 degrees.  
   
   
       9 . An antenna as specified in  claim 7  wherein said antenna element rows are arranged to provide two simultaneous row antenna beams, said two row antenna beams being offset from said pointing direction by opposite and substantially equal angles.  
   
   
       10 . An antenna as specified in  claim 9  wherein said antenna element rows comprise a plurality of antenna elements having a selected spacing and a signal combiner/divider arranged to provide signals to or from said elements of each row with opposite phase for adjacent elements.  
   
   
       11 . An antenna as specified in  claim 7  wherein said antenna element rows are arranged to provide one of two selectable row antenna beams, said selectable row antenna beams being offset from said pointing direction by opposite and substantially equal angles.  
   
   
       12 . An antenna as specified in  claim 11  wherein said antenna element rows comprise a plurality of antenna elements having selected spacing, a coupling matrix connected to said elements having at least two ports, each port corresponding to one of said selectable beams and a switch for selecting one of said ports.  
   
   
       13 . An antenna having a pointing direction, comprising three linear arrays of antenna element rows, each said array having a linear direction perpendicular to said pointing direction and forming an angle of about 60 degrees with the linear direction of the other arrays, each of said element rows being arranged to form at least one row antenna beam in a direction which is offset from said pointing direction in a plane perpendicular to said linear direction of its corresponding array, phase shifters arranged to change the phase of signals transmitted or received by antenna elements of each of said rows and a signal combiner/divider for each array arranged to couple signals between said phase shifters and a transmitter or receiver port of said array, and a switch for selecting one of said arrays for connection to a transmitter or receiver.  
   
   
       14 . An antenna as specified in  claim 13  wherein said row antenna beams of said element rows are offset from said pointing direction by an angle of 30 to 60 degrees.  
   
   
       15 . An antenna as specified in  claim 13  wherein said antenna element rows are arranged to provide two simultaneous row antenna beams, said two row antenna beams being offset from said pointing direction by opposite and substantially equal angles.  
   
   
       16 . An antenna as specified in  claim 15  wherein said antenna element rows comprise a plurality of antenna elements having a selected spacing and a signal combiner/divider arranged to provide signals to or from said elements of each row with opposite phase for adjacent elements.  
   
   
       17 . An antenna as specified in  claim 13  wherein said antenna element rows are arranged to provide one of two selectable row antenna beams, said selectable row antenna beams being offset from said pointing direction by opposite and substantially equal angles.  
   
   
       18 . An antenna as specified in  claim 17  wherein said antenna element rows comprise a plurality of antenna elements having selected spacing, a coupling matrix connected to said elements having at least two ports, each port corresponding to one of said selectable beams and a switch for selecting one of said ports.  
   
   
       19 . An antenna as specified in  claim 13  wherein said linear arrays are arranged within a decorative spoiler for mounting on an automobile.  
   
   
       20 . An antenna as specified in  claim 19  wherein said spoiler further includes at least one additional antenna.  
   
   
       21 . An antenna system for a vehicle comprising the antenna of  claim 13  and a control system for operating said phase shifters and said switch to cause said antenna to receive signals from a satellite, said control system being arranged to compensate for the location and directional orientation of said vehicle.  
   
   
       22 . An antenna system as specified in  claim 21  wherein said control system receives signals from a global positioning system to determine location of said vehicle.